Pharmacodynamics 3

Question 1

ribosomes: what?

Answer 1

responsible for cellular protein synthesis: translate mRNA to protein

Question 2

selective toxicity for ribosomes: how?

Answer 2

bacterial ribosomes are different for humans: 50 and 30S in bacteria, 80S in humans

Question 3

aminoglycosides? macrolides?

Answer 3

bactericidal: irreversible inhibition of 30S ribosome. bacteriostatic: reversible inhibition of 50S ribosome subunit.

Question 4

potency is a _____ based index? what does it mean?

Answer 4

dose-base index: how much of a drug you need to elicit an effect

Question 5

ED50: definition

Answer 5

drug concentration that produces 50% of maximum response. lower ED50 - more potency.

Question 6

therapeutic index: what?

Answer 6

index of drug safety: ratio of toxic dose to therapeutic dose aka TD50/ED50

Question 7

therapeutic dose: if close to 1? if less than 10?

Answer 7

1 = toxicities likely to occur.

Question 8

agonist: does 2 things? efficacy?

Answer 8

interacts with receptor + elicits response via receptor. high efficacy.

Question 9

antagonist: does what? efficacy?

Answer 9

interacts with receptor but doesn’t stimulate/elicit transduction. efficacy close to zero.

Question 10

efficacy: full agonist vs. partial vs. antagonist vs. inverse agonist

Answer 10

full agonist = max response, efficacy of 1. partial = between 0 and 1. antagonist = 0. inverse agonist

Question 11

competitive antagonist: does what? what does the D/R curve looks like?

Answer 11

combines with same receptor as agonist. parallel right shift in D/R curve, doesn’t reduce max R

Question 12

irreversible antagonists: D/R curve?

Answer 12

decreases in slope and maximum

Question 13

4 other types of antagonism (other than competitive and irreversible)

Answer 13

non-competitive antagonism. physiological. chemical. pharmacokinetic.

Question 14

non competitive antagonism: what and ex?

Answer 14

blocks receptor linkage aka downstream transduction mechanisms. ex: Ca entry blockers inhibit positive inotropes.

Question 15

physiological antagonism: what and ex?

Answer 15

agonist actions of two drugs work in opposite directions. ex: nitroprusside in hypertensive crisis

Question 16

chemical antagonism: what and ex?

Answer 16

one drug neutralizes another. ex: bicarbonate reduces gastric acitidy

Question 17

pharmacokinetic antagonism:what and ex?

Answer 17

one drug binds to another to change its pharmacokinetic properties. ex: reducing absorption of a drug

Question 18

drug response lessens over time: term for it?

Answer 18

tachyphylaxis = over a few minutes. tolerance = gradual loss of effectiveness

Question 19

6 mechanisms that reduce drug effectiveness

Answer 19

receptor alterations. mediators exhaustion. accelerated metabolism/inactivation of drug. inhibited metabolism/inactivation of drug. physiological adaptation. changes in gene expression.

Question 20

receptors alterations: 3 examples how it reduces drug effectiveness

Answer 20

conformational change: lowers tissue response. phosphorylation. downregulation of receptors.

Question 21

two key pharmacological principles

Answer 21

selectivity of drug action (not always specific = side effects). drug interactions.